it's a surprising finding. when I added Trizol to fully differentiated adipocytes culture to extract RNA, white adipocytes all floated while beige adipocytes remains attached on the culture plate.
I think it depends on the charge of different glycoprotein protein moieties on the surface of each cell type. you can try culture on glass tissue culture flask or falcon.
I saw a paper about this issue just now, quite interesting, they found PGC1a could inhibit cell adhesion gene expression in brown adipocytes.
Minsky, Neri, and Robert G. Roeder. "Inhibition of Adhesion Molecule Gene Expression and Cell Adhesion by the Metabolic Regulator PGC-1α." PloS one 11.12 (2016): e0165598.